X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/bbcf899f198faddcbd9abbe576ea4ae09257740d..0598d99d917545f1cf2e2a3a09e29cdbe70302ff:/auth1.c

diff --git a/auth1.c b/auth1.c
index 5e9b3aa5..7c010010 100644
--- a/auth1.c
+++ b/auth1.c
@@ -10,40 +10,30 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: auth1.c,v 1.10 2001/01/07 19:06:25 markus Exp $");
-
-#ifdef HAVE_OSF_SIA
-# include <sia.h>
-# include <siad.h>
-#endif
+RCSID("$OpenBSD: auth1.c,v 1.50 2003/08/13 08:46:30 markus Exp $");
 
 #include "xmalloc.h"
 #include "rsa.h"
-#include "ssh.h"
+#include "ssh1.h"
 #include "packet.h"
 #include "buffer.h"
 #include "mpaux.h"
+#include "log.h"
 #include "servconf.h"
 #include "compat.h"
 #include "auth.h"
+#include "channels.h"
 #include "session.h"
+#include "uidswap.h"
+#include "monitor_wrap.h"
 
 /* import */
 extern ServerOptions options;
-extern char *forced_command;
-
-#ifdef WITH_AIXAUTHENTICATE
-extern char *aixloginmsg;
-#endif /* WITH_AIXAUTHENTICATE */
-#ifdef HAVE_OSF_SIA
-extern int saved_argc;
-extern char **saved_argv;
-#endif /* HAVE_OSF_SIA */
 
 /*
  * convert ssh auth msg type into description
  */
-char *
+static char *
 get_authname(int type)
 {
 	static char buf[1024];
@@ -56,13 +46,12 @@ get_authname(int type)
 		return "rhosts-rsa";
 	case SSH_CMSG_AUTH_RHOSTS:
 		return "rhosts";
-#ifdef KRB4
+	case SSH_CMSG_AUTH_TIS:
+	case SSH_CMSG_AUTH_TIS_RESPONSE:
+		return "challenge-response";
+#ifdef KRB5
 	case SSH_CMSG_AUTH_KERBEROS:
 		return "kerberos";
-#endif
-#ifdef SKEY
-	case SSH_CMSG_AUTH_TIS_RESPONSE:
-		return "s/key";
 #endif
 	}
 	snprintf(buf, sizeof buf, "bad-auth-msg-%d", type);
@@ -70,27 +59,35 @@ get_authname(int type)
 }
 
 /*
- * read packets and try to authenticate local user 'luser'.
- * return if authentication is successful. not that pw == NULL
- * if the user does not exists or is not allowed to login.
- * each auth method has to 'fake' authentication for nonexisting
- * users.
+ * read packets, try to authenticate the user and
+ * return only if authentication is successful
  */
-void
-do_authloop(struct passwd * pw, char *luser)
+static void
+do_authloop(Authctxt *authctxt)
 {
 	int authenticated = 0;
-	int attempt = 0;
 	u_int bits;
-	RSA *client_host_key;
+	Key *client_host_key;
 	BIGNUM *n;
 	char *client_user, *password;
-	char user[1024];
+	char info[1024];
 	u_int dlen;
-	int plen, nlen, elen;
 	u_int ulen;
-	int type = 0;
-	void (*authlog) (const char *fmt,...) = verbose;
+	int prev, type = 0;
+	struct passwd *pw = authctxt->pw;
+
+	debug("Attempting authentication for %s%.100s.",
+	    authctxt->valid ? "" : "illegal user ", authctxt->user);
+
+	/* If the user has no password, accept authentication immediately. */
+	if (options.password_authentication &&
+#ifdef KRB5
+	    (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
+#endif
+	    PRIVSEP(auth_password(authctxt, ""))) {
+		auth_log(authctxt, 1, "without authentication", "");
+		return;
+	}
 
 	/* Indicate that authentication is needed. */
 	packet_start(SSH_SMSG_FAILURE);
@@ -99,93 +96,69 @@ do_authloop(struct passwd * pw, char *luser)
 
 	client_user = NULL;
 
-	for (attempt = 1;; attempt++) {
+	for (;;) {
 		/* default to fail */
 		authenticated = 0;
 
-		strlcpy(user, "", sizeof user);
+		info[0] = '\0';
 
 		/* Get a packet from the client. */
-		type = packet_read(&plen);
+		prev = type;
+		type = packet_read();
+
+		/*
+		 * If we started challenge-response authentication but the
+		 * next packet is not a response to our challenge, release
+		 * the resources allocated by get_challenge() (which would
+		 * normally have been released by verify_response() had we
+		 * received such a response)
+		 */
+		if (prev == SSH_CMSG_AUTH_TIS &&
+		    type != SSH_CMSG_AUTH_TIS_RESPONSE)
+			abandon_challenge_response(authctxt);
 
 		/* Process the packet. */
 		switch (type) {
-#ifdef AFS
-		case SSH_CMSG_HAVE_KERBEROS_TGT:
-			if (!options.kerberos_tgt_passing) {
-				verbose("Kerberos tgt passing disabled.");
-				break;
-			} else {
-				/* Accept Kerberos tgt. */
-				char *tgt = packet_get_string(&dlen);
-				packet_integrity_check(plen, 4 + dlen, type);
-				if (!auth_kerberos_tgt(pw, tgt))
-					verbose("Kerberos tgt REFUSED for %.100s", luser);
-				xfree(tgt);
-			}
-			continue;
 
-		case SSH_CMSG_HAVE_AFS_TOKEN:
-			if (!options.afs_token_passing || !k_hasafs()) {
-				verbose("AFS token passing disabled.");
-				break;
-			} else {
-				/* Accept AFS token. */
-				char *token_string = packet_get_string(&dlen);
-				packet_integrity_check(plen, 4 + dlen, type);
-				if (!auth_afs_token(pw, token_string))
-					verbose("AFS token REFUSED for %.100s", luser);
-				xfree(token_string);
-			}
-			continue;
-#endif /* AFS */
-#ifdef KRB4
+#ifdef KRB5
 		case SSH_CMSG_AUTH_KERBEROS:
 			if (!options.kerberos_authentication) {
-				/* packet_get_all(); */
 				verbose("Kerberos authentication disabled.");
-				break;
 			} else {
-				/* Try Kerberos v4 authentication. */
-				KTEXT_ST auth;
-				char *tkt_user = NULL;
-				char *kdata = packet_get_string((u_int *) &auth.length);
-				packet_integrity_check(plen, 4 + auth.length, type);
-
-				if (auth.length < MAX_KTXT_LEN)
-					memcpy(auth.dat, kdata, auth.length);
-				xfree(kdata);
-
-				if (pw != NULL) {
-					authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
-					if (authenticated) {
-						snprintf(user, sizeof user, " tktuser %s", tkt_user);
-						xfree(tkt_user);
+				char *kdata = packet_get_string(&dlen);
+				packet_check_eom();
+
+				if (kdata[0] != 4) { /* KRB_PROT_VERSION */
+					krb5_data tkt, reply;
+					tkt.length = dlen;
+					tkt.data = kdata;
+
+					if (PRIVSEP(auth_krb5(authctxt, &tkt,
+					    &client_user, &reply))) {
+						authenticated = 1;
+						snprintf(info, sizeof(info),
+						    " tktuser %.100s",
+						    client_user);
+
+ 						/* Send response to client */
+ 						packet_start(
+						    SSH_SMSG_AUTH_KERBEROS_RESPONSE);
+ 						packet_put_string((char *)
+						    reply.data, reply.length);
+ 						packet_send();
+ 						packet_write_wait();
+
+ 						if (reply.length)
+ 							xfree(reply.data);
 					}
 				}
+				xfree(kdata);
 			}
 			break;
-#endif /* KRB4 */
-
-		case SSH_CMSG_AUTH_RHOSTS:
-			if (!options.rhosts_authentication) {
-				verbose("Rhosts authentication disabled.");
-				break;
-			}
-			/*
-			 * Get client user name.  Note that we just have to
-			 * trust the client; this is one reason why rhosts
-			 * authentication is insecure. (Another is
-			 * IP-spoofing on a local network.)
-			 */
-			client_user = packet_get_string(&ulen);
-			packet_integrity_check(plen, 4 + ulen, type);
-
-			/* Try to authenticate using /etc/hosts.equiv and .rhosts. */
-			authenticated = auth_rhosts(pw, client_user);
-
-			snprintf(user, sizeof user, " ruser %s", client_user);
+		case SSH_CMSG_HAVE_KERBEROS_TGT:
+			packet_send_debug("Kerberos TGT passing disabled before authentication.");
 			break;
+#endif
 
 		case SSH_CMSG_AUTH_RHOSTS_RSA:
 			if (!options.rhosts_rsa_authentication) {
@@ -200,26 +173,22 @@ do_authloop(struct passwd * pw, char *luser)
 			client_user = packet_get_string(&ulen);
 
 			/* Get the client host key. */
-			client_host_key = RSA_new();
-			if (client_host_key == NULL)
-				fatal("RSA_new failed");
-			client_host_key->e = BN_new();
-			client_host_key->n = BN_new();
-			if (client_host_key->e == NULL || client_host_key->n == NULL)
-				fatal("BN_new failed");
+			client_host_key = key_new(KEY_RSA1);
 			bits = packet_get_int();
-			packet_get_bignum(client_host_key->e, &elen);
-			packet_get_bignum(client_host_key->n, &nlen);
+			packet_get_bignum(client_host_key->rsa->e);
+			packet_get_bignum(client_host_key->rsa->n);
 
-			if (bits != BN_num_bits(client_host_key->n))
+			if (bits != BN_num_bits(client_host_key->rsa->n))
 				verbose("Warning: keysize mismatch for client_host_key: "
-				    "actual %d, announced %d", BN_num_bits(client_host_key->n), bits);
-			packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
+				    "actual %d, announced %d",
+				    BN_num_bits(client_host_key->rsa->n), bits);
+			packet_check_eom();
 
-			authenticated = auth_rhosts_rsa(pw, client_user, client_host_key);
-			RSA_free(client_host_key);
+			authenticated = auth_rhosts_rsa(pw, client_user,
+			    client_host_key);
+			key_free(client_host_key);
 
-			snprintf(user, sizeof user, " ruser %s", client_user);
+			snprintf(info, sizeof info, " ruser %.100s", client_user);
 			break;
 
 		case SSH_CMSG_AUTH_RSA:
@@ -228,9 +197,10 @@ do_authloop(struct passwd * pw, char *luser)
 				break;
 			}
 			/* RSA authentication requested. */
-			n = BN_new();
-			packet_get_bignum(n, &nlen);
-			packet_integrity_check(plen, nlen, type);
+			if ((n = BN_new()) == NULL)
+				fatal("do_authloop: BN_new failed");
+			packet_get_bignum(n);
+			packet_check_eom();
 			authenticated = auth_rsa(pw, n);
 			BN_clear_free(n);
 			break;
@@ -246,43 +216,24 @@ do_authloop(struct passwd * pw, char *luser)
 			 * not visible to an outside observer.
 			 */
 			password = packet_get_string(&dlen);
-			packet_integrity_check(plen, 4 + dlen, type);
+			packet_check_eom();
 
-#ifdef USE_PAM
-			/* Do PAM auth with password */
-			authenticated = auth_pam_password(pw, password);
-#elif defined(HAVE_OSF_SIA)
-			/* Do SIA auth with password */
-			if (sia_validate_user(NULL, saved_argc, saved_argv, 
-				get_canonical_hostname(), pw->pw_name, NULL, 0, 
-				NULL, password) == SIASUCCESS) {
-				authenticated = 1;
-			}
-#else /* !USE_PAM && !HAVE_OSF_SIA */
- 			/* Try authentication with the password. */
-			authenticated = auth_password(pw, password);
-#endif /* USE_PAM */
+			/* Try authentication with the password. */
+			authenticated = PRIVSEP(auth_password(authctxt, password));
 
 			memset(password, 0, strlen(password));
 			xfree(password);
 			break;
 
-#ifdef SKEY
 		case SSH_CMSG_AUTH_TIS:
 			debug("rcvd SSH_CMSG_AUTH_TIS");
-			if (options.skey_authentication == 1) {
-				char *skeyinfo = NULL;
-				if (pw != NULL)
-					skeyinfo = skey_keyinfo(pw->pw_name);
-				if (skeyinfo == NULL) {
-					debug("generating fake skeyinfo for %.100s.", luser);
-					skeyinfo = skey_fake_keyinfo(luser);
-				}
-				if (skeyinfo != NULL) {
-					/* we send our s/key- in tis-challenge messages */
-					debug("sending challenge '%s'", skeyinfo);
+			if (options.challenge_response_authentication == 1) {
+				char *challenge = get_challenge(authctxt);
+				if (challenge != NULL) {
+					debug("sending challenge '%s'", challenge);
 					packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
-					packet_put_cstring(skeyinfo);
+					packet_put_cstring(challenge);
+					xfree(challenge);
 					packet_send();
 					packet_write_wait();
 					continue;
@@ -291,78 +242,57 @@ do_authloop(struct passwd * pw, char *luser)
 			break;
 		case SSH_CMSG_AUTH_TIS_RESPONSE:
 			debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
-			if (options.skey_authentication == 1) {
+			if (options.challenge_response_authentication == 1) {
 				char *response = packet_get_string(&dlen);
-				debug("skey response == '%s'", response);
-				packet_integrity_check(plen, 4 + dlen, type);
-				authenticated = (pw != NULL &&
-				    skey_haskey(pw->pw_name) == 0 &&
-				    skey_passcheck(pw->pw_name, response) != -1);
+				packet_check_eom();
+				authenticated = verify_response(authctxt, response);
+				memset(response, 'r', dlen);
 				xfree(response);
 			}
 			break;
-#else
-		case SSH_CMSG_AUTH_TIS:
-			/* TIS Authentication is unsupported */
-			log("TIS authentication unsupported.");
-			break;
-#endif
 
 		default:
 			/*
 			 * Any unknown messages will be ignored (and failure
 			 * returned) during authentication.
 			 */
-			log("Unknown message during authentication: type %d", type);
+			logit("Unknown message during authentication: type %d", type);
 			break;
 		}
-		if (authenticated && pw == NULL)
-			fatal("internal error: authenticated for pw == NULL");
-
-#ifdef HAVE_CYGWIN
-		if (authenticated && 
-		    !check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD,pw->pw_uid)) {
-			packet_disconnect("Authentication rejected for uid %d.",
-			(int)pw->pw_uid);
-			authenticated = 0;
+#ifdef BSD_AUTH
+		if (authctxt->as) {
+			auth_close(authctxt->as);
+			authctxt->as = NULL;
 		}
 #endif
+		if (!authctxt->valid && authenticated)
+			fatal("INTERNAL ERROR: authenticated invalid user %s",
+			    authctxt->user);
 
-		/*
-		 * Check if the user is logging in as root and root logins
-		 * are disallowed.
-		 * Note that root login is allowed for forced commands.
-		 */
-		if (authenticated && pw && pw->pw_uid == 0 && !options.permit_root_login) {
-			if (forced_command) {
-				log("Root login accepted for forced command.");
-			} else {
-				authenticated = 0;
-				log("ROOT LOGIN REFUSED FROM %.200s",
-				    get_canonical_hostname());
-			}
+#ifdef _UNICOS
+		if (authenticated && cray_access_denied(authctxt->user)) {
+			authenticated = 0;
+			fatal("Access denied for user %s.",authctxt->user);
 		}
+#endif /* _UNICOS */
 
-		/* Raise logging level */
-		if (authenticated ||
-		    attempt == AUTH_FAIL_LOG ||
-		    type == SSH_CMSG_AUTH_PASSWORD)
-			authlog = log;
-
-		authlog("%s %s for %s%.100s from %.200s port %d%s",
-			authenticated ? "Accepted" : "Failed",
-			get_authname(type),
-			pw ? "" : "illegal user ",
-			pw && pw->pw_uid == 0 ? "ROOT" : luser,
-			get_remote_ipaddr(),
-			get_remote_port(),
-			user);
-
-#ifdef USE_PAM
-		if (authenticated && !do_pam_account(pw->pw_name, client_user))
+#ifdef HAVE_CYGWIN
+		if (authenticated &&
+		    !check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD, pw)) {
+			packet_disconnect("Authentication rejected for uid %d.",
+			pw == NULL ? -1 : pw->pw_uid);
+			authenticated = 0;
+		}
+#else
+		/* Special handling for root */
+		if (authenticated && authctxt->pw->pw_uid == 0 &&
+		    !auth_root_allowed(get_authname(type)))
 			authenticated = 0;
 #endif
 
+		/* Log before sending the reply */
+		auth_log(authctxt, authenticated, get_authname(type), info);
+
 		if (client_user != NULL) {
 			xfree(client_user);
 			client_user = NULL;
@@ -371,14 +301,9 @@ do_authloop(struct passwd * pw, char *luser)
 		if (authenticated)
 			return;
 
-		if (attempt > AUTH_FAIL_MAX) {
-#ifdef WITH_AIXAUTHENTICATE 
-			loginfailed(user,get_canonical_hostname(),"ssh");
-#endif /* WITH_AIXAUTHENTICATE */
-			packet_disconnect(AUTH_FAIL_MSG, luser);
-		}
+		if (authctxt->failures++ > AUTH_FAIL_MAX)
+			packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
 
-		/* Send a message indicating that the authentication attempt failed. */
 		packet_start(SSH_SMSG_FAILURE);
 		packet_send();
 		packet_write_wait();
@@ -389,53 +314,49 @@ do_authloop(struct passwd * pw, char *luser)
  * Performs authentication of an incoming connection.  Session key has already
  * been exchanged and encryption is enabled.
  */
-void
-do_authentication()
+Authctxt *
+do_authentication(void)
 {
-	struct passwd *pw, pwcopy;
-	int plen;
+	Authctxt *authctxt;
 	u_int ulen;
-	char *user;
+	char *user, *style = NULL;
 
 	/* Get the name of the user that we wish to log in as. */
-	packet_read_expect(&plen, SSH_CMSG_USER);
+	packet_read_expect(SSH_CMSG_USER);
 
 	/* Get the user name. */
 	user = packet_get_string(&ulen);
-	packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
-
-	setproctitle("%s", user);
-
-#ifdef AFS
-	/* If machine has AFS, set process authentication group. */
-	if (k_hasafs()) {
-		k_setpag();
-		k_unlog();
+	packet_check_eom();
+
+	if ((style = strchr(user, ':')) != NULL)
+		*style++ = '\0';
+
+#ifdef KRB5
+	/* XXX - SSH.com Kerberos v5 braindeath. */
+	if ((datafellows & SSH_BUG_K5USER) &&
+	    options.kerberos_authentication) {
+		char *p;
+		if ((p = strchr(user, '@')) != NULL)
+			*p = '\0';
 	}
-#endif /* AFS */
+#endif
+
+	authctxt = authctxt_new();
+	authctxt->user = user;
+	authctxt->style = style;
 
 	/* Verify that the user is a valid user. */
-	pw = getpwnam(user);
-	if (pw && allowed_user(pw)) {
-		/* Take a copy of the returned structure. */
-		memset(&pwcopy, 0, sizeof(pwcopy));
-		pwcopy.pw_name = xstrdup(pw->pw_name);
-		pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
-		pwcopy.pw_uid = pw->pw_uid;
-		pwcopy.pw_gid = pw->pw_gid;
-#ifdef HAVE_PW_CLASS_IN_PASSWD
-		pwcopy.pw_class = xstrdup(pw->pw_class);
-#endif
-		pwcopy.pw_dir = xstrdup(pw->pw_dir);
-		pwcopy.pw_shell = xstrdup(pw->pw_shell);
-		pw = &pwcopy;
-	} else {
-		pw = NULL;
-	}
+	if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL)
+		authctxt->valid = 1;
+	else
+		debug("do_authentication: illegal user %s", user);
+
+	setproctitle("%s%s", authctxt->pw ? user : "unknown",
+	    use_privsep ? " [net]" : "");
 
 #ifdef USE_PAM
-	if (pw)
-		start_pam(pw);
+	if (options.use_pam)
+		PRIVSEP(start_pam(user));
 #endif
 
 	/*
@@ -443,50 +364,21 @@ do_authentication()
 	 * the server. (Unless you are running Windows)
 	 */
 #ifndef HAVE_CYGWIN
-	if (getuid() != 0 && pw && pw->pw_uid != getuid())
+	if (!use_privsep && getuid() != 0 && authctxt->pw &&
+	    authctxt->pw->pw_uid != getuid())
 		packet_disconnect("Cannot change user when server not running as root.");
 #endif
 
-	debug("Attempting authentication for %s%.100s.", pw ? "" : "illegal user ", user);
-
-	/* If the user has no password, accept authentication immediately. */
-	if (options.password_authentication &&
-#ifdef KRB4
-	    (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
-#endif /* KRB4 */
-#ifdef USE_PAM
-	    auth_pam_password(pw, "")) {
-#elif defined(HAVE_OSF_SIA)
-	    (sia_validate_user(NULL, saved_argc, saved_argv, 
-	    get_canonical_hostname(), pw->pw_name, NULL, 0, 
-		 NULL, "") == SIASUCCESS)) {
-#else /* !HAVE_OSF_SIA && !USE_PAM */
- 	    auth_password(pw, "")) {
-#endif /* USE_PAM */
-		/* Authentication with empty password succeeded. */
-		log("Login for user %s from %.100s, accepted without authentication.",
-		    user, get_remote_ipaddr());
-	} else {
-		/* Loop until the user has been authenticated or the
-		   connection is closed, do_authloop() returns only if
-		   authentication is successful */
-		do_authloop(pw, user);
-	}
-	if (pw == NULL)
-		fatal("internal error, authentication successful for user '%.100s'", user);
+	/*
+	 * Loop until the user has been authenticated or the connection is
+	 * closed, do_authloop() returns only if authentication is successful
+	 */
+	do_authloop(authctxt);
 
 	/* The user has been authenticated and accepted. */
 	packet_start(SSH_SMSG_SUCCESS);
 	packet_send();
 	packet_write_wait();
-	xfree(user);
-
-#ifdef WITH_AIXAUTHENTICATE
-	/* We don't have a pty yet, so just label the line as "ssh" */
-	if (loginsuccess(user,get_canonical_hostname(),"ssh",&aixloginmsg) < 0)
-		aixloginmsg = NULL;
-#endif /* WITH_AIXAUTHENTICATE */
 
-	/* Perform session preparation. */
-	do_authenticated(pw);
+	return (authctxt);
 }